Soft Flex beading wire is constructed of micro woven stainless steel wires:

Soft Flex Beading Wire is strong and flexible. It can be used with Czech Glass Beads, Swarovski Crystal Beads, Metal Beads and Gemstone Beads. All stainless steel used in Soft Flex wire is 100% recyclable. The spools and clips can also be recycled - just tear off the label and put the empty spool into your recycling bin. 

Soft Flex Satin Silver Clear Heavy Beading Wire Specifications:

• Color: Satin Silver Clear
• Category: Beading Wire
• Strength Test: 40 lbs - Heavy
• Number of Strands: 49
• Material: Stainless Steel 
• Diameter: 0.024 inch
• Quantity: This Soft Flex Satin Silver Clear Heavy Beading Wire is sold on a 30 ft spool